The present invention is related to dispensing apparatus with a metered discharge to feed a selected amount of loose material at a controlled rate dependent upon rotation of a metering element.
There are several forms of metered dispensing apparatus currently available and in predominant use in the agricultural industry for planting seeds and dispensing powdered fertilizer.
One form of metered dispensing apparatus makes use of a hopper with converging walls leading to an axial vane type metering shaft. The vanes are equiangularly spaced about the axis of the shaft. The shaft is usually housed within a semi-circular portion of the hopper that is in open communication with the hopper interior and discharge. Where several laterally spaced rows of material are to be dispensed from the hopper, the same vane metering shaft may extend across the full hopper width, servicing all of the discharge openings in unison.
Hoppers with multiple spaced discharge openings and with the vane type metering devices are very difficult to clean. For example, when a hopper has been utilized to apply a granulated weed killer, it becomes very desirable to completely clean the weed killer from the hopper prior to using the hopper for the application of seed. The difficulty is that the area between the discharge openings cannot be easily moved axially to the discharge openings. The vanes of the metering device cover the area between discharge openings and thereby prevent access for cleaning purposes. The vaned meter must therefore be rotated slowly several times while the material is being swept toward the discharge openings. This is obviously a tedious process.
U.S. Pat. No. 982,018 to C. E. Patric discloses a planting machine having a rotating distributing wheel with peripheral indentations rather than axial vanes for receiving seeds. The indentations are spaced angularly in a circular path about the wheel. Metal-to-metal frictional contact is made between the hopper and the rotating distributing wheel.
U.S. Pat. No. 254,957 to F. J. Grow illustrates a wheat feeder utilizing an axial vane metering device that is shaped somewhat like a ratchet wheel in cross section. Brushes are utilized to regulate and equalize flow of wheat through the vaned metering device.
U.S. Pat. No. 3,053,418 to Jordan discloses a seed sowing machine that utilizes, as a metering device, two pipes, one inside another. The outer pipe has two annular rows of holes spaced about the periphery. The holes of one row are staggered about the periphery in relation to holes of the other row. The inside pipe forms a base for the holes so seed will not fall through. The holes do not span the width of the hopper and the metering device rotates within a rigid housing at the bottom end of a hopper.
U.S. Pat. No. 3,055,145 to M. C. Hornung discloses a seed and fertilizer metering device. The metering device includes an elliptical groove formed about the shaft that fits in a mating cylindrical journal. The journal is slotted at the bottom side to allow feed through the elliptical groove. The feed material, if sufficiently flowable, could feed continuously through the open groove in both directions about the central rotational axis. The metering shaft is also in close proximity to the journal.
The present dispenser makes use of a helical metering arrangement that extends fully across the width of the associated hopper to accurately and consistently deliver metered amounts of material through one or more discharge orifices. Care is taken that the material does not meet with shearing forces between the metering shaft and hopper walls. The dispenser will automatically clean itself without requiring extra effort on the part of the operator.